I have been doing some pondering on animal Transfiguration lately, and I have a few things that have me stumps.
We knoe that inanimate objects can be turned into animals from the scene in the first book, but according to Gamp's Law, we know that magic can't be used to conjure food. Although, why people couldn't just kill the pig is a mystery to me, but I do have a few theories as to why this might be.
Could it be that animals conjured from inanimate objects just have the nutritional value of whatever they are transfigured from: like a bar of soap turned into a duck would really just still be the same as soap if a person tried to eat it?
What do you all think?